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1e13d733c2
initAlgorithm() method This allows 2 benefits: - algorithms can be subclassed and have subclasses add additional parameters/outputs to the algorithm. With the previous approach of declaring parameters/outputs in the constructor, it's not possible to call virtual methods to add additional parameters/ outputs (since you can't call virtual methods from a constructor). - initAlgorithm takes a variant map argument, allowing the algorithm to dynamically adjust its declared parameters and outputs according to this configuration map. This potentially allows model algorithms which can be configured to have variable numbers of parameters and outputs at run time. E.g. a "router" algorithm which directs features to one of any number of output sinks depending on some user configured criteria.
266 lines
12 KiB
Python
266 lines
12 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ShortestPathPointToLayer.py
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---------------------
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Date : December 2016
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Copyright : (C) 2016 by Alexander Bruy
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Email : alexander dot bruy at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Alexander Bruy'
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__date__ = 'December 2016'
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__copyright__ = '(C) 2016, Alexander Bruy'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import os
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from collections import OrderedDict
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from qgis.PyQt.QtCore import QVariant
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from qgis.PyQt.QtGui import QIcon
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from qgis.core import (QgsWkbTypes, QgsUnitTypes, QgsFeatureSink, QgsFeature, QgsGeometry, QgsPointXY, QgsFields, QgsField, QgsFeatureRequest,
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QgsMessageLog,
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QgsProcessingParameterDefinition,
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QgsProcessingUtils)
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from qgis.analysis import (QgsVectorLayerDirector,
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QgsNetworkDistanceStrategy,
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QgsNetworkSpeedStrategy,
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QgsGraphBuilder,
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QgsGraphAnalyzer
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)
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from qgis.utils import iface
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from processing.core.parameters import (ParameterVector,
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ParameterPoint,
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ParameterNumber,
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ParameterString,
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ParameterTableField,
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ParameterSelection
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)
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class ShortestPathPointToLayer(QgisAlgorithm):
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INPUT_VECTOR = 'INPUT_VECTOR'
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START_POINT = 'START_POINT'
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END_POINTS = 'END_POINTS'
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STRATEGY = 'STRATEGY'
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DIRECTION_FIELD = 'DIRECTION_FIELD'
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VALUE_FORWARD = 'VALUE_FORWARD'
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VALUE_BACKWARD = 'VALUE_BACKWARD'
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VALUE_BOTH = 'VALUE_BOTH'
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DEFAULT_DIRECTION = 'DEFAULT_DIRECTION'
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SPEED_FIELD = 'SPEED_FIELD'
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DEFAULT_SPEED = 'DEFAULT_SPEED'
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TOLERANCE = 'TOLERANCE'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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def icon(self):
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return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.svg'))
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def group(self):
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return self.tr('Network analysis')
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.DIRECTIONS = OrderedDict([
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(self.tr('Forward direction'), QgsVectorLayerDirector.DirectionForward),
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(self.tr('Backward direction'), QgsVectorLayerDirector.DirectionForward),
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(self.tr('Both directions'), QgsVectorLayerDirector.DirectionForward)])
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self.STRATEGIES = [self.tr('Shortest'),
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self.tr('Fastest')
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]
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self.addParameter(ParameterVector(self.INPUT_VECTOR,
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self.tr('Vector layer representing network'),
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[dataobjects.TYPE_VECTOR_LINE]))
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self.addParameter(ParameterPoint(self.START_POINT,
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self.tr('Start point')))
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self.addParameter(ParameterVector(self.END_POINTS,
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self.tr('Vector layer with end points'),
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[dataobjects.TYPE_VECTOR_POINT]))
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self.addParameter(ParameterSelection(self.STRATEGY,
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self.tr('Path type to calculate'),
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self.STRATEGIES,
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default=0))
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params = []
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params.append(ParameterTableField(self.DIRECTION_FIELD,
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self.tr('Direction field'),
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self.INPUT_VECTOR,
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optional=True))
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params.append(ParameterString(self.VALUE_FORWARD,
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self.tr('Value for forward direction'),
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'',
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optional=True))
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params.append(ParameterString(self.VALUE_BACKWARD,
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self.tr('Value for backward direction'),
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'',
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optional=True))
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params.append(ParameterString(self.VALUE_BOTH,
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self.tr('Value for both directions'),
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'',
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optional=True))
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params.append(ParameterSelection(self.DEFAULT_DIRECTION,
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self.tr('Default direction'),
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list(self.DIRECTIONS.keys()),
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default=2))
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params.append(ParameterTableField(self.SPEED_FIELD,
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self.tr('Speed field'),
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self.INPUT_VECTOR,
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optional=True))
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params.append(ParameterNumber(self.DEFAULT_SPEED,
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self.tr('Default speed (km/h)'),
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0.0, 99999999.999999, 5.0))
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params.append(ParameterNumber(self.TOLERANCE,
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self.tr('Topology tolerance'),
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0.0, 99999999.999999, 0.0))
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for p in params:
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p.setFlags(p.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
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self.addParameter(p)
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self.addOutput(OutputVector(self.OUTPUT_LAYER,
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self.tr('Shortest path'),
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datatype=[dataobjects.TYPE_VECTOR_LINE]))
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def name(self):
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return 'shortestpathpointtolayer'
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def displayName(self):
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return self.tr('Shortest path (point to layer)')
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def processAlgorithm(self, parameters, context, feedback):
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layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_VECTOR), context)
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startPoint = self.getParameterValue(self.START_POINT)
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endPoints = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.END_POINTS), context)
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strategy = self.getParameterValue(self.STRATEGY)
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directionFieldName = self.getParameterValue(self.DIRECTION_FIELD)
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forwardValue = self.getParameterValue(self.VALUE_FORWARD)
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backwardValue = self.getParameterValue(self.VALUE_BACKWARD)
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bothValue = self.getParameterValue(self.VALUE_BOTH)
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defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
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bothValue = self.getParameterValue(self.VALUE_BOTH)
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defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
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speedFieldName = self.getParameterValue(self.SPEED_FIELD)
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defaultSpeed = self.getParameterValue(self.DEFAULT_SPEED)
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tolerance = self.getParameterValue(self.TOLERANCE)
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fields = QgsFields()
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fields.append(QgsField('start', QVariant.String, '', 254, 0))
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fields.append(QgsField('end', QVariant.String, '', 254, 0))
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fields.append(QgsField('cost', QVariant.Double, '', 20, 7))
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feat = QgsFeature()
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feat.setFields(fields)
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writer = self.getOutputFromName(
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self.OUTPUT_LAYER).getVectorWriter(fields, QgsWkbTypes.LineString, layer.crs(), context)
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tmp = startPoint.split(',')
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startPoint = QgsPointXY(float(tmp[0]), float(tmp[1]))
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directionField = -1
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if directionFieldName is not None:
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directionField = layer.fields().lookupField(directionFieldName)
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speedField = -1
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if speedFieldName is not None:
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speedField = layer.fields().lookupField(speedFieldName)
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director = QgsVectorLayerDirector(layer,
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directionField,
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forwardValue,
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backwardValue,
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bothValue,
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defaultDirection)
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distUnit = iface.mapCanvas().mapSettings().destinationCrs().mapUnits()
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multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
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if strategy == 0:
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strategy = QgsNetworkDistanceStrategy()
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else:
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strategy = QgsNetworkSpeedStrategy(speedField,
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defaultSpeed,
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multiplier * 1000.0 / 3600.0)
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multiplier = 3600
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director.addStrategy(strategy)
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builder = QgsGraphBuilder(iface.mapCanvas().mapSettings().destinationCrs(),
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True,
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tolerance)
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feedback.pushInfo(self.tr('Loading end points...'))
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request = QgsFeatureRequest()
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request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
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features = QgsProcessingUtils.getFeatures(endPoints, context, request)
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count = QgsProcessingUtils.featureCount(endPoints, context)
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points = [startPoint]
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for f in features:
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points.append(f.geometry().asPoint())
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feedback.pushInfo(self.tr('Building graph...'))
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snappedPoints = director.makeGraph(builder, points)
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feedback.pushInfo(self.tr('Calculating shortest paths...'))
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graph = builder.graph()
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idxStart = graph.findVertex(snappedPoints[0])
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tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
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route = []
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total = 100.0 / count if count else 1
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for i in range(1, count + 1):
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idxEnd = graph.findVertex(snappedPoints[i])
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if tree[idxEnd] == -1:
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msg = self.tr('There is no route from start point ({}) to end point ({}).'.format(startPoint.toString(), points[i].toString()))
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feedback.setProgressText(msg)
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QgsMessageLog.logMessage(msg, self.tr('Processing'), QgsMessageLog.WARNING)
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continue
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cost = 0.0
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current = idxEnd
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while current != idxStart:
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cost += graph.edge(tree[current]).cost(0)
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route.append(graph.vertex(graph.edge(tree[current]).inVertex()).point())
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current = graph.edge(tree[current]).outVertex()
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route.append(snappedPoints[0])
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route.reverse()
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geom = QgsGeometry.fromPolyline(route)
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feat.setGeometry(geom)
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feat['start'] = startPoint.toString()
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feat['end'] = points[i].toString()
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feat['cost'] = cost / multiplier
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writer.addFeature(feat, QgsFeatureSink.FastInsert)
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route[:] = []
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feedback.setProgress(int(i * total))
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del writer
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